The invention relates generally to methods and devices used for reducing air resistance and drag on a body located within an air stream, and particularly to those methods and devices for reducing wind resistance and drag on moving vehicles.
When a non-streamline moving body moves through air at high speeds a low pressure area or xe2x80x9cvacuumxe2x80x9d usually is created behind the trailing or rearward end of the body. This is particularly true with large vehicles having a generally flat or block-shaped rearward end, such as truck trailers and the like. As a result, the moving body encounters significant aerodynamic resistance and drag.
As can be seen in FIG. 1, which shows a streamline or aerodynamic body 10 located within an air stream (as indicated by the arrows), there is very little air compression at the front of the body 10 and very little vacuum at the rear of the body 10 as air passes smoothly about the outer surfaces of the body 10. Thus, the body 10 moves through the air easily and with little aerodynamic resistance. In contrast, FIG. 2 shows a non-streamline body 12 with large, flat front and rear surfaces. As air encounters the body 12, a high degree of air compression is observed at the forward end of the body 12, with a significant vacuum being created at the rearward end of the body 12. Air rushes into the area of the vacuum to the rear of the body 12 creating turbulent air or vortices that increase the drag of body 12.
This effect is a particular problem with large and bulky wheeled vehicles, such as those used for transporting cargo where streamlined or aerodynamic designs are impractical. Such vehicles commonly include many trucks, tractor-trailers, buses, vans, RV""s, locomotives, railcars, and the like. Because of their design and large size, a significant amount of drag and air resistance is produced. Additionally, such vehicles usually travel over long distances where even the smallest reduction in drag and air resistance can result in a significant reduction in costly fuel consumption.
There are numerous methods that have been tried in the past to reduce drag in moving vehicles. And while much work has been done on improving the aerodynamics of the front end of vehicles, there has been less emphasis on improving the rearward or load carrying end, the design of which is oftentimes limited by cargo requirements. Those designs that do exist, however, are often cumbersome and can interfere with the normal operation and use of the vehicle, such as when opening and closing doors or accessing the cargo space of the vehicle, thereby making their use impractical. Many, if not most, of these methods require the use of an airfoil or air-deflecting surface for directing air inwardly from the rearward sides of the vehicle to disrupt the trailing vortical air flow. Other methods call for improving the aerodynamic design of the vehicle, such as that disclosed in U.S. Pat. No. 4,257,641.
Improvements are therefore needed for reducing drag and aerodynamic resistance in such vehicles without interfering with the normal use and operation of the vehicle and which provide a cost effective and easily implemented means for doing so.
An air channeler device is provided for use with a body having a forward and rearward end and located in an air stream for reducing wind resistance of the body. The air channeler has an air inlet for positioning within an air stream surrounding the body so that air is received in the inlet as the air stream moves about the body. An air discharge is provided for positioning at a generally central location of the rearward end of the body and has a width that is substantially less than the width of the rearward end of the body so that the air discharge is spaced inward from the edges of the rearward end. An air conduit couples to the body and has a generally tubular passageway that is in communication between the air inlet and the air discharge for directing air from the air inlet through the conduit to the discharge.
In more specific embodiments, the air conduit is formed in at least two sections that are releasably joined together so that the at least two sections can be engaged and disengaged from one another. One of the at least two sections may also be adapted for coupling to a movable portion of the body, which is movable between first and second positions, and wherein movement of the movable portion between the first and second positions causes engagement and disengagement of the at least two sections. A seal may also be joined to at least one of the two sections of the air conduit for providing sealing engagement of the two sections of the air conduit when engaged with one another.
In other embodiments, various features may be included. For instance, an air damper can be provided that is movable between open and closed positions for selectively closing off the air conduit to prevent air flow through the passageway. The width of the air discharge may be substantially less than the distance of the air discharge from the side edges of the rearward end of the body. The air discharge can be about 12 inches or less. The air inlet and air discharge may include opposite ends of the air conduit. Further, a coupling device for coupling the air conduit to the vehicle may be provided.
The air channeler device can also be provided in a vehicle having a forward end and a rearward end for reducing wind resistance of the vehicle. The device has an air inlet for positioning within an air stream surrounding the vehicle so that air is received in the inlet as the vehicle is moved in a forward direction. An air discharge located at a generally central location of the rearward end of the vehicle and having a width that is substantially less than the width of the rearward end of the vehicle is provided so that the air discharge is spaced inward from the edges of the rearward end. An air conduit is mounted to the vehicle and has a generally tubular passageway that is in communication between the air inlet and the air discharge for directing air from the air inlet through the conduit to the discharge.
In still another embodiment, an air channeler device for use with a vehicle having a forward and rearward end is provided for reducing wind resistance of the vehicle. The device has an air inlet for positioning within an air stream surrounding the vehicle so that air is received in the inlet as the vehicle is moved in a forward direction. An air discharge for positioning at the rearward end of the vehicle is also provided. An air conduit is coupled to the vehicle and has a generally tubular passageway that is in communication between the air inlet and the air discharge for directing air from the air inlet through the conduit to the discharge. The air conduit is formed in at least two sections that are releasably joined together so that the at least two sections can be engaged and disengaged from one another. One of the at least two sections is adapted to be mounted to a movable portion of the vehicle that is movable between first and second positions and wherein movement of the movable portion between the first and second positions causes engagement and disengagement of the at least two sections.
A method of reducing wind resistance of a body having a forward end and a rearward end that is located in air stream is also achieved by positioning an air inlet within an air stream surrounding the body so that air is received in the inlet as the air stream moves about the body. An air discharge is provided at a generally central location of the rearward end of the body. The air discharge has a width that is substantially less than the width of the rearward end of the body so that the air discharge is spaced inward from the edges of the rearward end. Air is allowed to pass through an air conduit having a generally tubular passageway that is in communication between the air inlet and the air discharge so that air is directed from the air inlet through the conduit to the discharge.
A method of selectively reducing wind resistance and slowing a moving vehicle having a forward end and a rearward end is also provided. The method comprises positioning an air inlet within an air stream surrounding the vehicle so that air is received in the inlet as the vehicle is moved in a forward direction. An air discharge is provided at a generally central location of the rearward end of the vehicle. The air discharge has a width that is substantially less than the width of the rearward end of the vehicle so that the air discharge is spaced inward from the edges of the rearward end. By selectively allowing air to pass through an air conduit having a generally tubular passageway that is in communication between the air inlet and the air discharge so that air is directed from the air inlet through the conduit to the discharge, wind resistance of the vehicle is reduced. Further, by restricting air flow through the passageway of the conduit, wind resistance is increased to thereby slow the vehicle.